On account of Theorem REF ,
we may assume that the equality holds in
(REF ) and
\(a_1(x)=(1+|x|^2)^p\)  with some \(p\in ((2-d)/2,1]\) .
For the proof of Theorem REF ,
we apply the Lyapunov method
(see, e.g., [1]} for diffusion processes
with singular diffusion coefficients)
by using the martingale characterization
of the generator of \(({\cal E}^{(1)},{\cal F}^{(1)})\) .
